/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.transforms.splittabledofn;



/** Definitions and convenience methods for reporting/consuming/updating backlogs. */

public final class Backlogs {

  /**

   * {@link RestrictionTracker}s which can provide a backlog should implement this interface.

   * Implementations that do not implement this interface will be assumed to have an unknown

   * backlog.

   *

   * <p>By default, the backlog partition identifier is represented as the encoded element and

   * restriction pair. See {@link HasPartitionedBacklog} for {@link RestrictionTracker}s that report

   * backlogs over a shared resource.

   */

  public interface HasBacklog {

    Backlog getBacklog();

  }



  /**

   * {@link RestrictionTracker}s which can provide a backlog that is from a shared resource such as

   * a message queue should implement this interface to provide the partition identifier. The

   * partition identifier is used by runners for various backlog calculations. Backlogs reported

   * with the same partition identifier represent a point in time reporting of the backlog for that

   * partition. For example, a runner can compute a global backlog by summing all reported backlogs

   * over all unique partition identifiers.

   *

   * <p>For example SplittableDoFn's which consume elements from:

   *

   * <ul>

   *   <li>a globally shared resource such as a Pubsub queue should set this to "".

   *   <li>a shared partitioned resource should use the partition identifier.

   *   <li>a uniquely partitioned resource such as a file range should set this to file name + start

   *       offset. Note that the default for {@link RestrictionTracker}s is to use the encoded

   *       element and restriction pair.

   * </ul>

   *

   * <p>Returns an immutable representation of the partition identifier.

   */

  public interface HasPartitionedBacklog extends HasBacklog {

    byte[] getBacklogPartition();

  }

}